There's a book about a Tai Ji teacher called TT Liang. It's called "Steal My Art".
The author, a student of Mr Liang, talks about his experiences as his student and the life lessons he absorbed during that time. It's been a while since I read it, but remember enjoying it.
The title refers to the tendency, especially in the older generations of teachers from Asia, to be rather secretive of their skills and their art. Mr Liang, however, gave his student a hint about how to gain it for himself - he encouraged him to 'steal it', by whatever means he was creative enough to do so.
My own teachers certainly have their stories of peeking over fences, and hiding in the bushes, trying to get glimpses of teachers practicing and teaching their 'indoor students'. Tales of plying them with gifts of cigarettes and tea, or whiskey and beer, of reciting stories of the teacher's teacher in ear shot in hopes of eliciting comment, and best of all practicing something wrong in front of them, something most teachers cannot abide to see, and cannot resist to correct.
Old school teachers also had a reputation for being brusque, with barely a good word to say, only terse correction and never ending utterances of 'No'! and 'Wrong'! It took a particular kind of grit for a student to stay the course, hard as it is to be constantly 'wrong'. It's hard to invest in loss, hard to fail, and hard to have your ego thrashed over and over again, perhaps alongside the rest of you.
Now I'm not saying this is the best way to teach, or that training should be so, but times were different then, and many of these guys had come from real, fighting, backgrounds. They played their cards close to their chests and were careful not to show their hands if they didn't need to.
My favorite story about TT Liang concerned a rude, obnoxious, bully who came to class, never listened to corrections, and who nobody wanted to work with due to his lack of control and tendency to inflict injury.
Apparently one day Mr Liang calls over the bully and hands him a piece of paper, and in front of the class, shakes his hand and says words to the effect of - Congratulations, you have finished the system, I can teach you no more, and I hereby award you this certificate of completion and wish you well on your journey.
Guy left and never came back.
So remember the old school .... and be careful if your teacher tells you - 'Yes, yes, very good', and apparently never finds anything wrong with what you do.
And be especially careful if they say - 'I don't think you can learn any more from me, I have taught you all I can. You have everything you need already. No need to come back' ....
It may not mean what you think it does ......